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Whale Fall Communities
What is a Whale Fall Community? A whale fall community is a whale carcass that is currently or has decomposed for animals to eat located at the bottom of the ocean. It creates a sudden, very concentrated source of nutrients for deep sea animals (NOAA, 2018). Animals the size of sharks to the size of plankton will feast on them. Some animals will even eat the bones. Due to the size and nutrient rich content of whales, one carcass supports multiple waves of organisms for many decades. The high carbon content in these areas allows for many of the same species that thrive in cold seeps and hydrothermal vents to be here as well (Science and the sea 2017). (Emma and Chris) Creatures of the Deep There are many animals that reside in the deep sea. The first process is called the mobile scavenger stage and can last up to 2 years. Animals that arrive at the first stage are usually sharks, some crabs, and larger fish. The enrichment opportunist stage, the second stage, can also last up to 2 years. Animals that arrive at this stage are worms and crustaceans and they feed on the left over fat and begin eating bone. The last stage is called the sulfophilic stage that can last up to 50 years. This stage is when mussels, clams and tube worms feed on the last of the bones. With only bone left, the bacteria breaks down the lipids that are inside the bone and creating sulfur which brings more bacteria and diverse species such as worms and snails (Smithsonian National Museum of Natural History). (Emma) One particular animal that can be found in a whale fall is the zombie worm. * Kingdom: Animalia * Scientific name: Osedax frankpressi * Phylum: Annelida * Class: Polychaeta * Order: Sabellida * Family: Siboglinidae The zombie worms arrive at the whale in the second part of decomposition called the opportunist stage. They are about 1 to 3 inches long. They have colorful feathery plumes that acts as gills as well as a root-like structure that absorb the nutrients they burrow. The worms that do the drilling are all females because the males are microscopic and live inside the females. The zombie worms attach themselves to the bone and begin to burrow into them. However, they do not eat the bone directly but instead they digest fats within the bone. The worms do not have a mouth or a stomach so they secrete an acid from their skin that helps dissolve the bone, releasing the fat and protein trapped inside. The bacteria in the body then digests the fat and protein. Because the zombie worm has been a relatively new find in the scientific community (2002), scientists have little knowledge about the zombie worm. There is no specified animal or animals that eat the zombie worm but the zombie worm only eats bone. They also don't have very much information on how the worm survives or thrives in the ocean depths. (Emma) The following video from the Smithsonian National Museum of Natural History shows the life of a whale, post mortem. https://ocean.si.edu/ocean-life/marine-mammals/life-after-whale-whale-falls Another creature that is associated with whale fall communities is the Hagfish. Its scientific name is Myxini. * Kingdom: Animalia * Phylum: Chordata * Subphylum: Vertebrata * Superclass: Cyclostomata * Class: Myxini * Order: Myxiniformes * Family: Myxinidae The Hagfish plays an important role in the first stage of decomposition associated with a whale fall, the mobile scavenger stage. The Hagfish, along with other "mobile scavengers" such as the Sleeper Shark (Somniosidae) and the Ratfish (Hydrolagus Collei) smells the dead carcass of a whale that has fallen into the abyssal zone. The Hagfish then travels a long distance to track down the dead whale using its keen sense of smell. Hagfish feed on dead whales' soft tissue and flesh for up to two years. Whale carcass consumption can be at a rate of 90- 130 lbs per day over a two-year period (Jeremiah, 2013). The Hagfish itself is an eel-shaped, slime-producing marine fish that is also commonly referred to as a slime eel. A unique trait of Hagfish is that they are the only animals alive on the planet that lack the presence of a vertebral column, but possess a skull. It is generally about 19 inches in length with a color that ranges from pink to blue-grey, and has eyes that are simply eye spots. Common prey of the Hagfish include marine invertebrates. Specific Hagfish prey include marine worms, shrimps, and hermit crabs. With regard to their nature as scavengers, Hagfish also feed on many dead marine organisms such as large fish and most notably whale carcasses. Hagfish are believed to be preyed upon by a handful of larger marine animals such as seals, as well as varieties of birds and mammals. However, marine predators often steer clear of Hagfish due to their repugnant looks and viscosity, as well as their unpleasant feeding habits in relation to their scavenging. The Hagfish uses its unique physical features as well as its biological advantages to survive in its habitat. For starters, they excrete micro-fibrous slime whenever they come in contact with a predator. This excreted mucus, combined with ocean water produces a combative substance that impairs the function of a predator's fish gills, disabling its ability to breathe. Additionally when captured by an attacker, they can tie themselves in an overhand knot and use their slime as a means of slithering their way away from the attacker's clutches. (Numair) The key to the third phase, called the sulfophilic stage, is the whale’s oil-rich skeleton. Lipids can account for 60 percent of whale bones’ weight. Bacteria break down these oils, producing sulfide in the process. Then, through a process called chemosynthesis, other bacteria oxidize the sulfide to make organic matter that organisms can feed on. Chemosynthetic bacteria support a diverse community of creatures, including mussels and clams (Science and the sea 2017). (Chris) Lastly, another animal that you can find in a whale fall during this stage is a deep water mussel called the Bathymodiolus childressi * Kingdom: Animalia * Phylum: Mollusca * Class: Bivalvia * Subclass: Pteriomorphia * Order: Mytiloida * Family:Mytilidae * Genus: Bathymodiolus * Species: B. childressi Another animal that can be found in a whale fall is the mussel. Mussels of the subfamily Bathymodiolinae thrive around underwater chimneys that emit hot fluids at deep sea hydrothermal vents, as well as at cold seeps and on sunken organic debris (sunken wood, whale falls). Despite the absence of light-driven primary production in these deep-sea ecosystems, mussels succeed reaching high biomasses in these harsh conditions thanks to chemosynthetic, carbon-fixing bacterial symbionts. These mussels are among the dominant macroorganisms in chemosynthesis-based communities around hydrothermal vents and cold-water seeps in the deep sea. In the darkness of these ecosysystems,far from any light to support photosynthesis, Bathymodiolus mussels depend on carbon-fixing bacteria harbored in their gill tissue; these bacteria oxidize sulphur or methane to generate the large amounts of energy required to fix inorganic carbon, which can then be used by the mussel host (reviewed in Duperron et al. 2009) Since the discovery of mussel symbioses about three decades ago our knowledge has increased, yet new findings are published regularly regarding their diversity, role and evolution. Mussels also breaks down lipids embedded in the bone. Lipids serve as 4-6% of a whale’s body weight, therefore is not expeditiously digested by limpets sea snails, clams and mussels, which is why this process stretches out for 50-100 years (eol.org 2018). (Chris). Relationships Because the hagfish, the zombie worms, and the mussels all arrive at the whale fall at different times in the decomposition fazes, they do not affect each other. The hagfish are a preyed upon species but not by many animals, as stated above. The zombie worms do not have any predators that scientists have found so far because there is almost nothing to their bodies. They would not be a sufficient meal for larger predators. The mussels are usually preyed upon by the surface by otters and birds because they can be picked at with beaks and claws. With animals in the deep ocean not having beaks or claws, they are left alone. Of the three species chosen, they would not interact with each other. (Emma and Numair) The childressi deep sea mussels do not interact with hagfish or zombie worms, they are however dependent on a symbiotic relationship within the ecosystem. A carbon fixed bacteria that the mussels harbor in their tissue is responsible for giving them their energy after the bacteria oxidizes sulfer and methane. (Chris) Fun Facts The zombie worm mates in a very odd way. The males live inside the females meaning that reproduction is very easy for zombie worms. (Emma) Also, females are the only ones that can produce the acid that is used to help them burrow into the bone because the males are microscopic. (Emma) To prevent choking on their own slime, Hagfish sneeze out slime from their nostrils, and tie their body into a knot to prevent the mucus from getting onto their face. (Numair) Although they are jawless, hagfish have two rows of tooth-like structures made of keratin that they use to burrow deep into animal remains as well as live prey. (Numair) The childressi is one of the only species of its genus to be found at whale falls. (Chris) Bathymodiolus mussels are found between depths of 600 meters and 3700 meters. (Chris) Sources Arnold, C. (2013). “Zombie” Worms Mate Inside Whale Bones – National Geographic Blog. Retrieved from https://blog.nationalgeographic.org/2013/03/26/zombie-worms-mate-inside-whale-bones/ Higgs, N. (n.d.) Whale Fall Ecosystems. Retrieved from https://www.nickhiggs.com/whale-fall-ecosystems.html Zombie Worm - Facts, Habitat, Diet and Information. (2018). Retrieved from https://animalfactsbit.blogspot.com/2017/04/zombie-worm-facts-habitat-diet-and.html NOAA. (2018). What is a whale fall?. Retrieved from https://oceanservice.noaa.gov/facts/whale-fall.html Waters, H. (2013). Zombie Worms Crave Bone. Retrieved from https://ocean.si.edu/ocean-life/invertebrates/zombie-worms-crave-bone Waters, H. (2012, October 17). 14 Fun Facts About Hagfish. Retrieved from https://www.smithsonianmag.com/science-nature/14-fun-facts-about-hagfish-77165589/ Zintzen, V., Roberts, C. D., Anderson, M. J., Stewart, A. L., Struthers, C. D., & Harvey, E. S. (2011, October 27). Hagfish predatory behaviour and slime defence mechanism. Retrieved from https://www.nature.com/articles/srep00131 Bell, J. (2016, October 23). Hagfish. Retrieved from https://www.britannica.com/animal/hagfish Flister, H. (2013, November 04). Introduction to the Myxini. Retrieved from http://www.ucmp.berkeley.edu/vertebrates/basalfish/myxini.html Knight, J. (2014). Atlantic Hagfish. Retrieved from http://www.seasky.org/deep-sea/atlantic-hagfish.html Bathymodiolus childressi. (2018, July 03). Retrieved from https://en.wikipedia.org/wiki/Bathymodiolus_childressi Bathymodiolus childressi - Overview. (n.d.). Retrieved from http://www.eol.org/pages/4733719/overview Symbioses between deep-sea mussels (Mytilidae: Bathymodiolinae) and chemosynthetic bacteria: Diversity, function and evolution. (2008, November 25). Retrieved from https://www.sciencedirect.com/science/article/pii/S163106910800228X Whale Falls. (n.d.). Retrieved from https://www.scienceandthesea.org/articles/201003/whale-falls